Hmm - I am in the gradual process of switching (and possibly remaining committed to both) to Fuji from Nikon. I have an old Nikon D90 and the Fuji XT-1.
I won't dwell on what I like about the Fuji system but I do want to give you a cautionary note on the XT-1 for wildlife photography. I think you'll find it a lateral move at best relative to even older Nikons.
My current solution is to keep the D90 with the Nikon 80-400 on it for birds and wildlife and the Fuji for everything else. For me, replacing the D90 with a D7200 would be the best bang for the buck move. I am curious to hear the reaction to the upcoming XT-2 with the 100-400 but I would be surprised if the focusing is as effective as the D7200/NIkon 80-400 combo for any action photography.
I love the image quality of the XT-1 but consistent focus has been an issue with me for people shots in low light in a way that even my older Nikon handles better. Some of it me learning the new system but I think you will also find that moving the focus point, looking thru EVF on the small camera is a more deliberate, slower process than your Nikon.
If wildlife is a big part of your photography, I might suggest hanging on to your D7000 and telephoto lens and make sure the Fuji XT-1 meets your needs there.
